Warm-Bloodedness in an Ocean Fish Stuns Evolutionists

It's a big, round fish called the opah, found in deep waters around the earth and looking a bit like someone's goldfish that seriously outgrew its bowl. Some fish, like tuna and sharks, can control temperature in parts of the body. This one can keep its whole body warm, giving it improved performance in the coldness of the depths. It's the first example of whole-body endothermy in a fish, raising new questions about the evolution of a complex trait.

The story caught the attention of many new...